public class cie {
    class Solution {
        public int peakIndexInMountainArray(int[] arr) {
            int left =0;
            int right =arr.length-1;
            while(left<right){
                int mid = left+(right-left+1)/2;
                if(arr[mid]>arr[mid-1]){
                    left = mid;
                }
                else{
                    right = mid-1;
                }
            }
            return left;
        }
    }
}
